How to find an equation of line parallel to a line?

If two lines are parallel, then they have the same slope.  Take the slope
of the line that you know, and use it for the new line.  If you also need to
find the intercept of the new line, then you need some more information ...
the intercept is not the same as the line that you know.

A=bxh3.2x1.8=5.76 centimeters square